Recent work in preservation of female fertility as well as new information on the nature of spermatogonial stem cells has prompted an investigation into the possibility of an effective clinical-grade procedure for the cryopreservation of cells and/or tissue.
Cryopreservation of reproductive cells and/or tissues has become an increasingly important methodology for fertility preservation. Success of autologous, cryopreserved ovarian tissue transplantation in patients has shown the ability of transplanted tissue to restore fertility in women and has generated live births. Currently, there are no methods for male patients that restore fertility or allow for future generation of new gametes in the event that their fertility is compromised due to testis damage. Cryopreservation of testicular cells and/or tissue prior to any fertility-compromising condition or therapy allows for future cell/tissue transplantation back to the autologous donor so that they regain the ability to naturally conceive their own biological children. Alternatively, these cells may be used to create new sperm outside the body through germ cell maturation protocols.
A procedure to preserve male fertility must be proven safe before it can be used in humans. Regulations and guidances set up by agencies such as the Food and Drug Administration (FDA) describe the procedures and systems that must be put into place before a product can be deemed safe to use in humans. Investigational techniques for cryopreserving testicular tissue and cells have been tested and reported by several groups; however, a clinical-grade protocol for the cryopreservation of human testicular cells or tissue has not been previously described. All previous studies used protocols non-compliant with current Good Tissue Practice (cGTP) standards, non-clinical-grade reagents, and/or animal products that made them unfit for clinical use. Additionally, no sterility testing was reported in these studies to ensure the absence of microbial contamination.